For enhancing the appearance and architectural merit of walls or ceilings, it is frequently required to add a decorative pattern in selected areas; this is particularly effective when applied to existing rough-textured ceilings of sprayed-on acoustic material.
It has been well known to utilize a stiff stencil, temporarily held against or fastened to the surface, configured with openings that define the regions to be embossed by adding new material, e.g. by spray or trowel, while masking off areas that are not to receive the new material.
There is a particular problem that arises when it is attempted to utilize such a stencil to mask a rough-textured surface: failure of the stencil to conform to the topography of the rough-textured surface introduces random irregularities at the edges of the stencil openings, rendering the edges of the finished embossed pattern rough and fuzzy instead of yielding the desired clean-cut reproduction of the pattern.
The stencil needs to be made compliant enough to be pressed in place to conform closely to the topography of the rough-textured surface, and to remain in close conformity, especially at the edges of the stencil openings, while the embossing material is applied. This requires the stencil material to be highly compliant so that it can stretch and expand as required to conform to the hills and valleys of the texture, but it must be non-elastic to prevent any loss of conformity while applying the embossing material.
Suitable compliant stencil material tends to be excessively flimsy and generally difficult to handle since it is susceptible to stencil damage and/or distorted pattern registration. For satisfactory deployment, special procedures are required particularly if the stencil pattern is unusually open and/or complex, and/or it is to be applied to a ceiling, to which the invention is mainly directed.